Cylinder head for hot-gas reciprocating engines



J. A. l.. YzER 2,616,250

CYLINDER HEAD FOR HOT-GAS RECIPROCATING ENGINES Nov. 4,"1952 Filed Aug. 4, 1950 E INVIgNToR. JACOBUS ALBERTUS Lows@ 'vz ER 'AGENT Patented Nov. 4, 1.952

HEAD FOB HQT-GAS BEGIPROCATING ENGNES Jacobus.: Albertus Louisa Yzer, Eindhoven, Netherlailclak assi nor t Hartford` National. BankY andllrust Qompany, Hartford, Connu trustee.

Application August 4, 1950,v Serial'No. 177,602/ In the Netherlands August 9, 1949-` (Cl. (io-24:).

4' ClaimSs 1 This invention relates generally te het rccrrccatineenei. es h in.. o are to be understood to i cati-.nc machines and-reine@ ne atinsfacccrdins to the reversed hcteeas reciproeating engine orincip.. More. particular-1r.. the invention relates to novel, heater head con.- Structcn for VSuch crieinefe.v

In the. constructions hitherto. known.;l the. cylinder ,containing the. piston o disnlacer. is sur..- rounded by a second cylinder riding the, Werk: ing space of the engine. second. cylinder generally comprises channels. for the working medium. of the engine. These ehannelsform part of the channel system; of the heat eXQhanger aS- Scciatecl with the Working space... Because. of the regularly occurring; comparatively high cycle pressure of the engine, the. second cylindermust have a. comparatively Strong: walt Such a. strong wall is normally furnished by the provision ofv a thick wall, due to which the. engine; llead-v is. comparatively heavy. This. may sometimes; con,- stitute a disadvantage if, for example, the engine is required to have a small weight. This is of more particular importance inI regard to traction engines, and notably those, to, he. used as air.- craft engines.l

In several constructions, the: exchange of heat to.4 the working medium or the. engine occurs through the wall of the aforesaid cylinder and so is adversely affected by the. considerable: thickness of this wall.

The presentv invention has fon its purpose to provide the head of* a hot gas reciproca-ting engine with a wall having a small' thickness and yet a suilcient strength to withstand the. aforesaid engine pressures. To this end, the hot-gas reciprocating engine according to the invention has the feature that-the wall of the engine head, which is subject to the intermittent internal pres,- sures of the Working medium, is made substantiallyy in the form of part of a sphere extending past its meridian section.

In this manner it is ensured that the wall formed as part of a sphere has av small; thickness coupled with sufficient4 strengthJ to withstand the comparatively high cycle pressure. In addition, as stated above, the heat transfer through this Wall is materially improved' dueto its smaller thickness..

In a suitable embodiment, the space bounded by the Wall formed as part of aspire-re comprises channels for the Working medium of the, engine. These channels form part off one or more heat exchangers of the engine.

Since a. comparatively highv temperature and pressure prevail in the heahfd space of,` the; hot-` gasl reciprocating engine, the wall bounding the working space is heavily loaded, as indicated hereinbefore. Additionally, this wall is subject to comparatively high strains; due to heat; expansion. If: this. Wall is. secured to other construe.- tional partsk of the engine Where; the; temperature is comparatively high,v severeA temperature strains may also occur atY these points. of attachment.; In order to avoid this, the hot-gas. reciprocating engine according to the invention has the feature that the wall in the form of part of a sphere surrounds the hote-space of the engine at. least. in part, and the said Wall' is secured to, one or vmore other constructional parts of the.. engine ata cold area of the latter.

In various embodiments of this engine, there may be a comparatively great clearance volume in the space bounded by the: wall formed as part of a sphere, byl which the enlcienoy of the. engine is adversely affected. Therefore, in. general, it will be of importance that, according to. one cmbodiment oi the invention, the space bounded by the aforesaid spherically shaped wall is. partly occupied by lling pieces. Oi course, the latter may be solid or hollow.

In a suitable embodimentof4 the invention, the spherically shaped wall comprises. means for increasing the heat transfer from the wall tothe working medium. For example, projectionsv or tubes for indirect heating may be included there.- with to thus increase the heat transferv through the wall. They wall may alternatively be pro,- vided with tubes containing a heat-.transmitting medium, thus ensuring indirect. heating of" the working medium.

In orderv that the invention may-be more fully understood and readily carried into eiiect, it. will now be described indetail with reference to the accompanying drawing, given` by: way of example, wherein:

Figure 1 is a vertical crossesectional View, taken along section line I.l ofv Figure 2r, of the cylinderof a hot-gas. engine showing a heater head with oneA embodiment of the invention applied thereto wherein substantially no heat exchange occurs through the wall formed as part oi a sphere;

Figure 2. is a horizontal cross-sectional view of the cylinder shown` in. Figure 1 and taken along section line IL-II therein; and

Figure` 3 is a, vertical cross-.sectional view of the cylinder ofy a hot-gas engine showing a heater head with another embodiment of the invention applied thereto wherein the heat exchange does occur substantially throughthe` wal-l formed as part of a sphere.

In the cylinder i' shown in Figures 1 and 2', a displacer 2'- and a piston 3 reciprocate in conventionalf manner. The displacer and piston are linked to a crank shaft in a, known manner (not shown) and' reciprocatel with the usual constant phase difference. The space above the displacer 2 is the hot space, whereas the space between kthe displacer 2 and the piston 3 is `the cold space. The hot space is surrounded by a wall 4 formed as part of a sphere which extends past its meridian section. The space boundedv ted in alternate relationship by common walls I3. With this heat exchanger, the exchange of heat between the combustion gases and the working medium takes place substantially through the aforesaid common walls I3 of the channels 5 and 6. It will be apparent that a much smaller amount of heat exchange will occur through the portions of the cylinder wall I4 bounding the channels 5 at their inner peripheries. The combustion gases enter the heater at 1 and follow the contour of the wall 4 in a radially directed passageway defined between the said wall 4 and a similarly shaped wall I6 spaced therefrom. 'Ifne now of the combustion gases in the substantially radial direction is ultimately stopped by an annular delecting plate I1 which has elongated tongs I5 extending into each of the open-topped channels 5 to just short of the bottoms I8 thereof. Thus, there is caused a doubling back of the ow of the combustion gases in the said channels 5 prior to their nal exit via the outlet 8. The working medium flows through the channels B and passes through the regenerator 9 and cooler II! to the cold space; the communication between said channels 6 and the hot chamber being the apertures I9. The clearance in the part of a sphere portion, which is not occupied by the channels of the heat exchanger just described hereinbefore, is filled with parts II, so that the clearance volume may be comparatively small.

The wall 4 of the engine head is secured to other constructional parts of the engine at a cold area; namely, at a point level with the cold terminal surface of the regenerator as by means Aof the flange I2 and bolts 2l.

In the embodiment of the invention shown in Figure 3, parts similar to those shown in Figure 1 bear the same reference numerals. In this second embodiment, the combustion gases enter the heater at "I and escape at 8 as before. vI-Iowever, they do not dip into channels such as channels 5 in Figure 1, none -being present. Instead, they pass over the spherically shaped wall 4 and give off their heat to the working medium through ribs 2D xed to the said wall 4. Ribs, indicated at may be xed to the walls vof channel 6 for better heat exchange Withthe working medium therein. vThe latter passes through channels 6, regenerator 9 and cooler I0 to the cold space in the usual manner. In this embodiment, also, the space bounded by the spherically shaped wall 4 is lled in part with members il, thus minimizing the clearance volume. Here, however, the filling members Il are on the inner sides of the channels 6 so that direct exchange through the wall 4 is possible over the entire surface thereof. V

In this embodiment, the wall 4 of the engine head is likewise secured to other constructional parts of the engine at a cold area; namely, on a level with the cold terminal surface of the regenerator, by means of a iiange I2 and bolts 2|.

It will be appreciated that, in addition to the aforesaid constructions of the heat exchangers 4 per se, that is, the channel and'heat exchange surface arrangementsmany different constructions may be used.

What I claim is:

1. A hot-gas reciprocating engine comprising a cylinder enclosing a hot area and a cold area, means separating said hot and cold areas, an engine head, said engine head having a wall surrounding part of said hot area and being subjected to the internal pressure of the working medium enclosed thereby, means securing said wall to the engine at said cold area, said wall being shaped substantially as part of a sphere across the meridian section thereof.

2. A hot-gas reciprocating engine comprising a cylinder enclosing a hot area and a cold area, means separating said hot and cold areas, an engine head, said engine head having a wall surrounding part of said hot area and being subjected to the internal pressure of the working medium enclosedy thereby, means securing said 4wall to the engine at said cold area, said wall being shaped substantially as part of a sphere across the meridian section thereof and heat exchanger means in said head for said working medium, said heat exchanger means comprising channels in a space bounded by said wall.

3. A hot-gas reciprocating engine comprising a cylinder enclosing a hot area and a cold area, means separating said hot and cold areas, an engine head, said engine head having a wall surrounding part of said hot area and being subjected to the internal pressure of the working medium enclosed thereby, means securing said wall to the engine at said cold area, said wall being shaped substantially as part of a sphere across the meridian section thereof, heating means on .one side of said wall, and heat exchanger means in said head for transferring heat from said heater to said working medium in the hot area, said heat exchanger means comprising channels in a space bounded by said wall.

4. A hot-gas reciprocating engine comprising 'a cylinder enclosing a hot area and a cold area, -means separating said hot and cold areas, an engine head, said engine head having a wall surrounding part of said hot area and being subjected to the internal pressure of the working medium enclosed thereby, means securing said wall to the engine at said cold area, said wall being shaped substantially as part of a sphere across the meridian section thereof, heating means on the external side of said wall. said heating means having .an inlet opening at the meridian point of said wall, said wall having projections thereon for increasing the heat transfer `qualities thereof, and lheat exchanger means in said head for transferring heat from said heater -to the working medium in the hot area, said heat exchanger means comprising channels in a space bounded by said wall.

JACOBUS ALBERTUS LOUISA YZER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PA'IENTS Number Name Date 1,389,780 Peck Q Sept. 6, 1921 1,912,785' Mills June 6, 1933 I 2,463,130 van We'enen Mar. 1, 1949 Stigter Mar. 22, 1949 

